That is, according to Bethesda Games Studios' Todd Howard. Who during a live-stream said that it will be "a long time" before we get to see more on either game and that "it’s not something we’re going to be talking about at E3". Which in the case of The Elder Scrolls 6 makes sense as that title, as far as we know, is the game due after Starfield.
Which would place it at least three-years after whenever Starfield is due - best case scenario. According to reports, the single-player RPG in style of an Elder Scrolls and Fallout and a brand new sci-fi IP from Bethesda will be a cross-gen release - meaning that it's likely to launch on both PS4/PS5 and Xbox One/Xbox Scarlet. In addition to PC.
With the next gen consoles due late next year odds are we'll get a full Starfield reveal next year with the launch to follow pretty soon thereafter. And when laid out like that, the no-show for BGS titles at E3 2019 doesn't sound so bad. In the words of Todd Howard, "Patience, please."